The invention concerns a device for arranging and removing pipette tips, wherein the pipette tips are arranged in apertured plates, the apertured plates being stacked in layers above each other in a magazine in a space-saving fashion.
Nearly every biological or medical laboratory uses specialized reciprocating pumps for handling and dosing the smallest of fluid volumes, so-called pipettes. In order to prevent contamination of the liquids and solutions being dispensed with the pipettes, contact with the fluid is effected via exchangeable disposable tips made from plastic which are attached to the lower end of the pipette. Same are utilized in great quantities in every laboratory.
The tips of the pipettes can be obtained in bulk form in bags and must then be individually attached to the pipettes by hand. This procedure has the intrinsic danger that the tips must be handled and therefore can become contaminated. In addition, this procedure is extremely time-consuming when a large quantity of pipettes is involved.
For ease of use it is therefore possible to purchase pipette tips attached to supports normally consisting of plastic, wherein the supports can be sealed by lids. The supports have apertured plates, wherein most manufacturers or retailers maintain a standard orthogonal 8.times.12 or 6.times.10 grid in dependence on the size of the pipette tips. In this fashion, easy removal of the pipette tips is guaranteed even in the event of multiple channel pipettes.
Sterile pipette tips are often required during laboratory work. Therefore, the supports are usually heatable up to approximately 120.degree. C. so that the tips can be sterilized (treated in an autoclave) with moist heat prior to use. Such supports will be designated below as autoclave boxes.
In practice not only the pipette tips but, in particular, the autoclave boxes themselves constitute disposable articles, although they could, in principle, be utilized a plurality of times. The reason for this is that a reattachment of the tip by hand in the laboratory is too time-consuming and involves too much effort so that an autoclave box of this type is delivered along with each delivery of attached tips. Since this box must also be of very stable construction in order to withstand the pressure loads occurring when disposing the pipettes into the tips, a relatively large amount of material is required for its production. This leads to increased environmental pollution during manufacture and distribution (an individual carrier has to be produced, transported and packaged for 96 or 60 tips in each case) and requires the user to solve the problem of disposing of large amounts of plastic waste, causing pollution.
A device of the above-mentioned kind is known in the art from the brochure "Pipettenspitzen von Rainin sind Spitze" Rainin pipette tips are tops! from the company Kleinfeld Labortechnik. Herein, a device has a retaining element comprising a narrowing on the lower end of the magazine, wherein release is effected by inserting the hand into the upper end of the magazine and pressing against the vertically stacked layers of pipette tips. The lower apertured plate thereby bends somewhat away from the narrowing as a result of which same is released or the narrowing moves aside. Towards this end it is necessary to insert the hand into the magazine from above. This results in an uncomfortable hand operation, particularly for the last layer located in the magazine. Insertion of the hand is associated with the danger of soiling the inside of the magazine and thereby the pipette tips. In addition, this type of construction leads to severe limitation in the number of layers which can be accommodated within a magazine.
A device of the above mentioned kind is furthermore known in the art from WO 92/01514. In this device, aperture plate-like mountings have holding tabs which serve for lifting the mounting, having the uppermost layer of pipette tips, for introduction to a support. The lifting of the mounting and the introduction of same having the tips into the support is a tedious manual operation considering the large quantity of tips which are necessary and which, in addition, has the danger of soiling the pipette tips. Furthermore, the pipette tips are not optimally stacked since the configuration of the spacers prevents mutual engagement to the extent which would be possible based on their geometry.
A device of the above mentioned kind is also known in the art from DE 92 16 674 U1. In this device support plates having layers of pipette tips are stacked above another and snapped into each other to form a magazine. The uppermost support plate is always removed and placed on a pan for laboratory use. In contrast to WO 92/01514, this device has the advantage that there is no need for introduction of the tips into the support, however the above mentioned disadvantages are not avoided.
The underlying purpose of the invention is to configure a device of the above-mentioned kind in such a fashion that a comfortable handling is possible and that the magazine can accept a large number of layers with the danger of soiling the objects being eliminated.